In a conventional copying machine, a hopper-shaped toner supplying unit is provided in the main body to supply a developing device with toner, and the toner is sent to be supplied to the developing device by means of an auger or the like. When the toner supplying unit becomes empty, it is removed from the developing device and the toner is replenished from a spare toner bottle. However, replenishing the toner in this way causes the toner to be scattered over and dirties the hands or clothes, thereby making the toner replenishment troublesome.
To solve this problem, Japanese Laid-Open Patent Application No. 5-150644 discloses a mechanism where a toner cartridge attachable to and detachable from the toner supplying unit is used instead of the toner bottle to replenish the toner. With this toner cartridge, a toner replenishing opening is formed on the surface of the cylindrical wall of an airtight cylindrical container filled with the toner, and a shutter plate, which is slidable along the surface of the cylindrical wall in the direction of circumference, is provided on the surface of the cylindrical wall to cover the toner replenishing opening.
On the other hand, at the toner supplying unit in the copying machine main body, an engagement shifting mechanism is provided to a holder unit that supports a portion of the surface of the cylindrical wall of the toner cartridge. The engagement shifting mechanism shifts the toner replenishing opening from the opening position to the closing position and vice versa as the container rotates so as to engage with the shutter plate. This mechanism enables the user to open the toner replenishing opening when the toner cartridge is attached to the toner supplying unit in the copying machine main body, thereby making it unnecessary to open the toner replenishing opening outside of the copying machine in advance. Thus, the toner will not be scattered over, and the manipulation and job efficiency of the toner replenishment is upgraded.
However, with the above-described toner cartridge, the user can open the shutter plate when the toner cartridge is removed from the toner supplying unit. Thus, the toner may be scattered over or undesirable materials may enter through the opening erroneously.
In addition, although the user can open the toner replenishing opening by rotating the container when the toner cartridge is attached to the toner supplying unit, he must confirm visually the position of the container at the relative angle of rotation with respect to the toner replenishing opening when it is open. To be more precise, the position is confirmed when a plane surface provided at the end to serve as a checking mark has become horizontal. For this reason, the user must pay a full attention when rotating the container, and it is often that he re-closes the toner replenishing opening by rotating the container more than necessary. Thus, neither the manipulation nor job efficiency of the toner replenishment is enhanced satisfactory with this toner cartridge.